1. Field of the Invention
The present invention relates generally to telecommunications systems and methods for limiting the usage of mobile telephones, and specifically to providing user-defined limits on mobile telephone usage based on increments of time or money.
2. Background and Objects of the Present Invention
Cellular telecommunications is one of the fastest growing and most demanding telecommunications applications ever. Today it represents a large and continuously increasing percentage of all new telephone subscriptions around the world. A standardization group, European Telecommunications Standards Institute (ETSI), was established in 1982 to formulate the specifications for the Global System for Mobile Communication (GSM) digital mobile cellular radio systems.
With reference now to FIG. 1 of the drawings, there is illustrated a GSM Public Land Mobile Network (PLMN), such as cellular network 10, which in turn is composed of a plurality of areas 12, each with a Mobile Services Center (MSC) 14 and an integrated Visitor Location Register (VLR) 16 therein. The MSC/VLR areas 12, in turn, include a plurality of Location Areas (LA) 18, which are defined as that part of a given MSC/VLR area 12 in which a mobile station (MS) 20 may move freely without having to send update location information to the MSC/VLR area 12 that controls the LA 18. Each Location Area 12 is divided into a number of cells 22.
Mobile Station (MS) 20 is the physical equipment, e.g., a car phone or other portable phone, used by mobile subscribers to communicate with the cellular network 10, each other, and users outside the subscribed network, both wireline and wireless. The MS 20 may also include a Subscriber Identity Module (SIM) card 13, or other memory, which provides storage of subscriber related information, such as a subscriber authentication key, temporary network data, and service related data (e.g. language preference).
The MSC 14 is in communication with at least one Base Station Controller (BSC) 23, which, in turn, is in contact with at least one Base Transceiver Station (BTS) 24. The BTS is the physical equipment, illustrated for simplicity as a radio tower, that provides radio coverage to the geographical part of the cell 22 for which it is responsible. It should be understood that the BSC 23 may be connected to several base transceiver stations 24, and may be implemented as a stand-alone node or integrated with the MSC 14. In either event, the BSC 23 and BTS 24 components, as a whole, are generally referred to as a Base Station System (BSS) 25.
With further reference to FIG. 1, the PLMN Service Area or cellular network 10 includes a Home Location Register (HLR) 26, which is a database maintaining all subscriber information, e.g., user profiles, current location information, International Mobile Subscriber Identity (IMSI) numbers, and other administrative information. The HLR 26 may be co-located with a given MSC 14, integrated with the MSC 14, or alternatively can service multiple MSCs 14, the latter of which is illustrated in FIG. 1.
The VLR 16 is a database containing information about all of the Mobile Stations 20 currently located within the MSC/VLR area 12. If a MS 20 roams into a new MSC/VLR area 12, the VLR 16 connected to that MSC 14 will request data about that Mobile Station 20 from the HLR database 26 (simultaneously informing the HLR 26 about the current location of the MS 20). Accordingly, if the user of the MS 20 then wants to make a call, the local VLR 16 will have the requisite identification information without having to reinterrogate the HLR 26. In the aforedescribed manner, the VLR and HLR databases 16 and 26, respectively, contain various subscriber information associated with a given MS 20.
Currently, the billing system of the cellular network differs from that of the Public Switched Telephone (wireline) Network (PSTN). Unlike the PSTN network, subscribers in the cellular network can be charged not only on a per month basis for local calls, but also on a per call basis depending on the plan purchased. For example, a subscriber can choose a plan that allots a certain number of minutes of air time for a set fee before being charged for air time usage. The amount of air time usage is based not only on calls placed from the MS, but also on calls received by the MS.
It is therefore difficult for many subscribers to accurately predict or control the amount they are charged for cellular service, especially when the MS 20 is being used by another party not responsible for billing. For example, when a business provides mobile phones to its employees or when a parent gives a mobile phone to their children, there is no existing procedure for allowing the subscriber to set limits on the amount of air time or charges incurred on the MS 20. In addition, if an MS 20 is stolen, the person in wrongful possession typically has ample time to place numerous calls for unlimited durations before the MS 20 is reported stolen and service is discontinued.
One known method of controlling mobile telephone usage is the prepaid service feature, which is provided by many network operators. This feature is used by network operators to encourage new subscribers with poor credit history to purchase wireless services. For example, an operator may sell to such a subscriber a specified amount of usage which is allocated to the subscriber. Once that specified amount is reached, the MS will no longer function until the subscriber purchases additional usage from the operator. However, the subscriber must pay in advance for the service, and is unable to modify or reset the usage limits independently.
It is therefore one object of the invention to allow subscribers to define usage limits for their MS, with or without the assistance of the network operator, based on charging information or the amount of air time.